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aitrh tetra @strat IMPROVEMENT IN STEAM GENERATORS.

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T0 ALL WHOM IT MAY CONCERN:

y Be it known that I, ELI THAYER, of the city, county, and State of NewYork, have invented a new and improved. Mode of Generating Steam; and Ido hereby declare that the following is a full and exact descriptionthereof, reference being had to the accompanying drawings, and to theletters of reference marked thereon.

The nature of my invention consists in so constructing and arranging theditferent parts of a steam generator, that, while the tire surface maybe very great and exposed to the highest possble heat, there shall be aconstant and rapid circulation of water and steam over every part of it,preventing the injurious heating of the metal of the generator, and theformation or adhesion of stea'm globules upon its inner surface. Thismode of construction (as, will be shown hereafter) will also securecheapness, simplicity, and compactness of form, with the greatestpossible'safety, etlciency, and economy in use.

To enable others skilled in the art to make and usel my invention, Iproceed to give a description of its construction and mode of operation.

Figure 1 represents a longitudinal vertical section.

Figure 2 represents4 a transverse vertical section i u front of' thebridge wall and through the furnace.

Figure 3 represents the furnace front.

Figure 4 represents a single tube of the generator on a larger scalethan shown in the other figures, for the purpose of exhibiting moreclearly its construction and connection with the supply anddischarge-chambers of the boiler. As these tubes are al'l constructedand attached in the same way, and differ only in length and size, adescription of one will be a description of all. l

In this figure, a represents a pipe or tube of metal, one and a halfinches internal diameter, one end of which is closed by being weldedtogether, lled with a plug, or covered by a cap. The other end is openand securely screwed into the side of the discharge-chamber e, at thepoint d. b represents a metallic pipe or tube, whose external diameteris less than the internal diameter of the pipe a, and lying within a.This pipe, t, is open at both ends, one end being securely screwed intothe supply chamber of the boiler, at the point c. The pipe b mayproperly be called a supply pipe, and the pipe a a discharge pipe.Suppose now that water is poured into the supply-chamberfuntil it risesseveral inches above the point c; the water will ow through `the supplypipe b, and back through the space between the outer surface of b andthe inner surface of a, into the dischargechamber e, until it rises inthe discharge-chamber to the same height as in the supply-chamber. lNewif the supply-chamber f, and the discharge-chamber e, have nocommunication with each other, except as above described, below thesurface of the water, and if the capacity of the discharge-chamber e benot very much greater than the capacity of the space between the pipes aand '6, then when sucient heat is applied to the pipe a, (which ishorizontal or nearly so,) there will be formed a rapid circulation ofwater through the pipe b, and of water and steam through the spacebetween the two pipes into and through the discharge-chamber e. If thewater in the supply-chamberfstands three feet above the point u, and thetubes a and b be respectively one Jand a halt` and three-fourths inchinternal diameter, and not exceeding twelve feet in length, they may beembedded in the burning coal of a powerful furnace throughout theirentire length, without injury, so rapid is the circulation of water andsteam V'through and between them, and so swiftly is the heat of themetal carried away in steam. If now, instead of this single combinationof a and b, we suppose several hundred such, with a. correspondingincrease of` the size of the chambers e and f, the first connected abovewith a steam-chamber f' into which it discharges, and the otherconnected with a water-chamber from which it receives its supplywe shallhave a very correct idea of the steam generator represented by gs. 1, 2,and 3.

Figure 5 represents a horizontal section of the supply-chamber f, (fig.1,) and of the discharge-chambers e and e. The chamber e is inserted forthe purpose of showing how the power of a steamgenerator of this kindcan be doubled by having a furnace and tubes, c c d d, (fig. 1,) on'each side of the supply-chambery".

We proceed now to a more full description of the construction and modeof operation of this steam generator, and for this purpose will use thesection represented by iig. g h j is a plain cylinder to beunade ofsuicient strength to sustain any required pressure, and of capacity inproportion to the extent of the tire surface of tubes connected with itby means of the chambers e e andf. These chambers together form `asurface of the four sides, and one end of arectangular-`parallelopi'pedon, excepting that, inside the cylinder thatportion of the two sides between the chambers e and e is wanting. Thewidth of these chambers is most conveniently made less than the diameterof the cylinder, so that Athe water may flow around thcdischarge-chambcrs vc and e', into the supply-chamber f, so long as anywater may remain in the cylinder. The supply-chamber only extends ashigh as the bottom i 7' of the cylinder, but the discharge-chambers cand c extend up' into the cylinder above the high-water line u, orperhaps one-third of the length of the cylinder. These chambers havetheir bases in the same 'horizontal plane, which is so much bclow thelowest tier of the steam and water pipes, that-the adjacent portion ofthe chambers becomes .the sediment extractor of the boiler, and shouldbe supplied with blow-cti` cocks at or near x, (iig. 1.) y representsthe bridge wall, built of solid masonry from the bottom of the ash-pitIt, and extends entirely across the furnace and as high as neededpatleast several inches above the top of the feed-chamber m m. rIhis wallshould be' built at the`same time that the pipes passing through it areinserted in their places so as to make the work perfectly tight andcompact about them. .s s represont the furnace, and m mthc feed-chamber.Between thi's chamber and the furnace, each of which has doors openingthe entire width of thefurnace front, as shown in iig. 3, there areseveral tiers of pipes as seen in figs. 1 and 2. The number and size ofthe pipes of this generator mustv vary according to the power required.For a boiler of one hundred horse power, I usc pipes, for the outside,of extra strong iron, and of one and a half inch internal diameter. Theinner pipes are ot ordinary thickness and three-fourths of an inchinternal diameter. I In a boiler of the rpower above named, there wouldbe about one hundred and sixty double pipes, of the lcind just named,each twelve feet long, and placed in the furnaceas shown in fig. 2. Thelower tier of these pipes, z'. e., those between the ash-pit and thefurnace s s, are six inches apart, between centres, and. having thewelded ends resting onr a bearing bar in front, serve as the tubularsupporters of gratos, as described in'my patent of August 1, 1865. Thewelded ends of the other long pipes pass through a cast-ironfplatesecurely built 'into the mason work three or four inches back of thefurnace front, (fig. 3,)-and are therefore fro-e to move backward andforward as the pipes may expand or contract, without in anydegrcelstrainin g the threadsby which the pipes are attached to thedischarge-chamber c. The welded ends of the short pipes, viz, those backof the furnace and feed-chamber, are sustained by the bridge wall. Thenumber of these will of course depend upon the height of the furnace andfeed-chamber, but in the present plan, as seen in g. 2, there wouldbcrtwo ytiers bach of the furnace s s, and one tier back of thefeed-chamber m fm, about thirty-six in all. As the external diameter ofthe outside pipes is about two inches, we should have as the 're surfacein the steam generator, above described, one thousand a'nd sixty-eightsquare feet. This estimate does not include the surface of the chambersef and c', around which the draught should be made to pass. The depth ofthe furnace, from the bottom'of the pipes over it to the gratos, iseight inches 5 of the feed-chamber, which has pipes for gratos, fiveinches. No two pipes are nearer to each other than the length of theirexternal diameter. Suppose now that the cylinder of which a verticalsection/,through its axis, is represented by g h (fig. 1,) is filledwith water to some point between a and u, the high and low-waterr lines,having the upper partof the cylinder, marked o, asthe `steam space. Thewater hows through the inner pipes, entering at the points c c c, andreturns between the two pipes, entering thc discharge-chamber c, at allthe points ol d d. The water will then stand on the same level in c asin j'. .A (In case the second dischargechamber c is constructed in aboiler for future use, when it may be needed, it should, until such use,have a communication withf, so as to be a part of the supply-chamber.)We now ll the furnace with a wood fire the immediate e'ect is to producesteam inthe spaces between the outer and inner pipes; this steam pressesequally towards the supply apertures c e c, and the discharge aperturesd al d, and a part escapes through both or is condensed, but very soonthe force of the steam drives the water 'entirely out of thedischarge-chamber c, and there is established a` constant and rapidcurrent through the pipes and between them, from c to d, the motivepower of which is the diiferencevin weight between the column of waterand the column of steam. lAfter the wood in the furnace has becomethoroughly ignited, coal should be shovelled into the feed-chamber andallowed to fall among the pipes till the spaces between them are full.The pipes make the coal easily permeated by the heat and gases from thefire below, by partly ,sustaining its weight and thus preventing itsmassing together or clogging. In this way the coal is burned 'in actualcontact with the rc surface of the boiler to any extent that may bedesired. As soon as the fire needs cleaning the furnace is opened andthe ashes sifted through the grate. The coal in this furnace willconsume much sooner than that lying among the pipes above the furnace.Hence the furnace may be nearly empty while the space above it is fullof partly consumed coal. In this case the furnace should be replenishedwith fresh coal. The combustible gases arising from this must traverseand permeate the already ignited coal above, thus securing the niostperfect combustion. For the purpose of removing any cinder or otherobstruction which may get among the pipes lying between the furnace andfeed-chamber, I have provided the doors w w, in the walls of thegenerator, as seen in g. 2,'through which, with a common slashbar, everypoint in the many tiers of pipes can be reached. It may in some cases bedesirable to haveeven a second feed-chamber a'bovc m m, or a feedingdoor, even intholtop of the structure, above all the pipes, for thepurpose of Ithrowing down coal to be consumed in contact with the pipes,but the plan above given is probably the best for ordinary use. Instead,also, of the discharge-chamber e, which all the pipes have in common,(figs. 1 and 5,) there might be -a separate discharge pipe for eachdouble pipe, a b, (fig. 1,) or one discharge-pipe for several of thedouble pipes, but this plan would be more complicated and expensive thanthe one above described, of having a common discharge-chamber for alllthe pipes in which steam is formed. It will be observed that the supplyaperture for each double pipe, a 6, is c, (lig. `1,) while the dischargeaperture for each and all of the double pipes is z, the upper end of thedischarge-chamber e, l

We .have thus far described the steam generator without dwellingparticularly upon its most important feature, namely, the several pipesor tiers of pipes between the feed-chamber m m, and the furnace s s.While these pipes constitute the most effective part of the generator inth;- production of steam, on account of their contact with theincandescent coal, they also' subserve another very important purpose towhich we now invite attention. When 'the coal is shovellod into thefeed-chamber and allowed to fall among these pipes, it does not occupyor iill all the space between them; under each pipe there will be leftan air-space as long as the pipe and as wide as its diameter, averagingabout one inch in depth, while between the pipes in the same horizontaltier the coal lies very lightly, as its weight is mainly or entirelysustained by the adjacent pipes. It is obvious, then, that this minutedivision of the coal by the supporting tubos greatly facilitates thepassage of air through the fuel for the support of combustion. It,however, the coal should be of very great depth', for the purpose ofcontaining or covering a largenuniber of tubes, it vmight be necessaryto admit air from the furnace front directly under a part or all of thepipes so embedded in the coal. We'see, then, that these pipes betweenthe feed-chamber and the furnaee, or,l (if the furnace be also filledwith thenn) between the feed-chamber and the grate, serve to support thecoal, to increase air-spaces in it, thereby promoting combustion, and togenerate steam.

hey also cifectually prevent the formation of clinker, for the heat ofthe Iire is so rapidly carried away by the passing water and steam, thatthe coal and ashes among the pipes cannot be melted. With referencetherefore, to the mechanical effect of these pipes, as above described,embedded in the coal, whether one tier or more, I give'theni the name ofthe upper grate. This grate may be used in connection with my steamgrate, patented March 28th, April 11th, and August Ist, 1865, or inconnection with any other grate. It may be used with such a steamgenerator as above described or with any other, of which, as of theabove, it may form a part. It may be made either of double pipes, asabove described, or it may be made of ordinary single pipes. Thecirculation of water and steam through the pipes composing it may beeffected by a discharge-chamber, as set forth, or by any othercontrivance; they may constitute the whole of a steam generator or onlya part of it, and maybe used in stoves, ranges', gratos, orire-places indwelling-houses, for' heating, or in furnaces for the production ofsteam. It may not be necessary, though it is pertinent, to say here thatthis4 invention is based upon new views of radiant heat, and is a.reduction of such views to practice. In accordance with this new theoryI find that the steam generated-in these embedded pipes constituting theupper grate is made by heat which would otherwise be of little or nouse,and does not, therefore, materially diminish the power of the tire foraccomplishing otherwork. In the drawings and description above given, Ihave represented a vertical boiler rfor containing the steam yandwater,'but a horizontal one could, perhaps, in many locations, he usedwith better economy. I have also represented a bridge wall, but this maybe dispensed with by bringing the dischargechamber forward to the backend of the furnace. Thisv method would be preferable with a horizontalboiler lying above the pipes and parallel with them.

Having now described its construction and mode of operation, what Iclaim as my invention,'and desire to secure by Letters Patent, is-

1. The discharge-chamber e, in combination with a tubular steamgenerator, substantially as set forth.

2. The arrangement of the several doors n fh, w w, for feeding the fuelamong the pipes constituting the upper grate, and for clearing them ofcinder or other obstructions, substantially as set forth.

3.' 'Ihe feeding-chamber m m, substantially as set forth.

4'. The upper grate, substantially as set forth.

' ELI THAYER.

Witnesses B. FRANKLIN CLARK, D. C. HoLBnooK.

